User can open and launch Microsoft Office Outlook in more than one or multiple windows or instances. When user clicks on Microsoft Outlook shortcut or icon on desktop or in Start Menu, an additional Outlook program’s instance with window will be opened, instead of bring to front the existing or currently opened Outlook program’s window.

The ability to open multiple windows of Outlook is the default behavior of Office productivity software, including Office Outlook 2010, 2007, 2003 and XP. However, some users may dislike the ability to have many Outlook windows, especially users with a keyboard or mouse with an “Email” key that can be accidentally pressed frequently.

For information, there is only one instance of Outlook.exe process running at a time, but the single process can span out many additional windows of Outlook. To avoid or prevent opening multiple Outlook windows, add the /recycle switch parameter to the command line target of the Outlook’s shortcut or icon.

Note: User may need to manually create a new shortcut which points to Outlook.exe in Program Files folder, if the system-installed shortcut does not allow Target to be amended or modified. The new shortcut to Outlook can be saved to desktop, pin to Taskbar or Start Menu, or even replace the system-installed shortcut for the trick to work.

To force Outlook to always has a maximum of one window only, right click on the shortcut or icon that runs Outlook, and select Properties. Then, at the end of Target textbox, append the /recycle, and click OK.

Allow Only One Window of Outlook

For hotkey built into keyboard or mouse, user has to identify the program the control the action taken when the hotkey is pressed, and edit the command line option for the option accordingly with additional /recycle switch.